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A Radial Injection Tracer Experiment in a Confined Aquifer, Scarborough, Ontario, Canada
Author(s) -
Palmer Carl D.,
Nadon Robert L.
Publication year - 1986
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.1986.tb01008.x
Subject(s) - aquifer , tracer , hydraulic conductivity , hydrology (agriculture) , groundwater , sampling (signal processing) , environmental science , soil science , geology , geotechnical engineering , soil water , electrical engineering , engineering , filter (signal processing) , nuclear physics , physics
A radial injection tracer experiment was conducted in Scarborough, Ontario, as part of a program to evaluate the feasibility of using a confined aquifer, underlying the Canada Centre building site for the storage of chilled and/or heated water for a seasonal thermal energy storage system. Water was injected into the aquifer for five hours before a salt solution was added as a tracer. This tracer was injected into the aquifer over a period of four hours at a rate of 22.7 1/s. Injection of the water into the aquifer continued for an additional 1 5 hours following injection of the salt solution. Samples were collected from a monitoring well located 6.54 meters from the injection well. A sampling device was installed prior to the injection experiment to permit the collection of water samples at different elevations within the screened portion of the monitoring well. The samples which were collected at five different elevations at various times, both during and following the salt injection, were analyzed for specific conductance and chloride concentration. The data suggest that the aquifer is inhomogeneous and that the ratio of the hydraulic conductivity to porosity increases from the lowest sampling port to the highest sampling port near the top of the aquifer. A linear relationship was obtained between the time of arrival of the tracer and the apparent resistivity of the formation. This linear relationship was used to calibrate the apparent resistivity log of the injection well to provide a continuous characterization of the vertical variation in the hydraulic conductivity/porosity ratio across the full thickness of the aquifer. Data analysis also suggests that the dispcrsivity parameter varies linearly with the time of arrival of the tracer. The combination of geophysical logs with tracer experiments may permit detailed characterization of the hydraulic properties of aquifers.